What is a major advantage of using constant variables in programs?

Using constant variables in programs provides a significant advantage as they help prevent accidental value changes. This characteristic is particularly beneficial during development and debugging phases. When a variable is declared as a constant, its value is fixed and cannot be altered throughout the program's execution. This immutability ensures that critical values (such as configuration settings, important numeric thresholds, or any fixed values necessary for computation) remain unchanged, which minimizes the risk of introducing bugs due to unintended modifications.

By ensuring that certain values remain constant, developers can also make their code easier to read and maintain. When other programmers (or even the original programmer returning to the code later) see a constant variable, they understand it is intended to be a fixed value, which can lead to fewer misunderstandings about the code's functionality.

In contrast, while there might be advantages in terms of memory efficiency or execution speed related to the use of constants, these are not the primary reason for utilizing them. Constants are not designed to have multiple values, which directly contradicts their purpose. Therefore, the key benefit is the protection against accidental changes, which contributes to more reliable and maintainable code.